title: Knockdown of SPARC leads to decreased cell-cell adhesion and lens cataracts during post-gastrula development in Xenopus laevis.
abstract: SPARC is a multifunctional matricellular glycoprotein with complex, transient tissue distribution during embryonic development. In Xenopus laevis embryos, zygotic activation of SPARC is first detected during late gastrulation, undergoing rapid changes in its spatiotemporal distribution throughout organogenesis. Injections of anti-sense Xenopus SPARC morpholinos (XSMOs) into 2- and 4-cell embryos led to a dose-dependent dissociation of embryos during neurula and tailbud stages of development. Animal cap explants derived from XSMO-injected embryos also dissociated, resulting in the formation of amorphous ciliated microspheres. At low doses of XSMOs, lens cataracts were formed, phenocopying that observed in Sparc-null mice. At XSMOs concentrations that did not result in a loss of axial tissue integrity, adhesion between myotomes at intersomitic borders was compromised with a reduction in SPARC concentration. The combined data suggest a critical requirement for SPARC during post-gastrula development in Xenopus embryos and that SPARC, directly or indirectly, promotes cell-cell adhesion in vivo.
authors.affiliation: Department of Microbiology & Immunology, University of Michigan Medical School, Ann Arbor, 48109-5620, USA.
authors.forename: My-Hang
authors.initials: MH
authors.lastname: Huynh
authors.forename: Shu Jun
authors.initials: SJ
authors.lastname: Zhu
authors.forename: Alexandra
authors.initials: A
authors.lastname: Kollara
authors.forename: Theodore
authors.initials: T
authors.lastname: Brown
authors.forename: Rudolf
authors.initials: R
authors.lastname: Winklbauer
authors.forename: Maurice
authors.initials: M
authors.lastname: Ringuette
mesh_terms: D000818:Animals; D002386:Cataract / Q000235:genetics* / Q000378:metabolism; D002448:Cell Adhesion; D055785:Gene Knockdown Techniques; D007908:Lens, Crystalline / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D015676:Osteonectin / Q000235:genetics / Q000378:metabolism*; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis / Q000196:embryology* / Q000235:genetics / Q000378:metabolism
chemical_list: D015676:Osteonectin; D029867:Xenopus Proteins